Cutting tool and system for coring a bowl using a lathe

ABSTRACT

A cutting tool piece is provided including a rear portion and a lead portion, the lead portion including a front section having an upper side angled downwardly and forwardly and a lower side angled upwardly and forwardly to form a transverse lead cutting edge. The rear portion includes a hole to secure the tool piece to a cutting tool and transverse cutting edges extending outwardly from side walls of the front section. A system is also described for cutting a bowl by coring out an interior portion of a wood block by applying the cutting tool which is curved and rotatably mounted to a post. Its lead end with the tool piece attached creates a circular groove. The cutting tool is advanced on a path which curves toward the central axis of the lathe.

[0001] This invention relates to a cutting piece, a cutting tool, asystem for forming a bowl utilizing a lathe, and a method for using theaforementioned system.

[0002] Lathes are used in the art of carving wood pieces by spinningwood pieces at sufficient speed and applying a sharp instrument to thewood piece for patterning or carving. The lathe typically includes aflat horizontal bed with rails mounted on the bed. Typically a supportblock or tool rest for supporting a cutting tool is slidably mounted onthe bed rails. The cutting tool may be manually applied to the face of awood block, using the support block or tool rest as a fulcrum tomanipulate the tool upon the wood. When cutting tools are manuallyapplied, accurate, consistent patterning of the wood piece is difficultto achieve. Cutting tools have also been secured upon the lead edge of acutting member which is slidably or rotatably secured to the supportblock or tool rest. Sliding the support block along the bed rails to aposition adjacent to the wood piece allows for selective application ofthe cutting piece by rotating or sliding the cutting member upon thesliding block.

[0003] The use of a lathe machine to construct bowls is known. A bowlmay be constructed using a lathe by manually applying a cuttinginstrument to carve out an interior portion of the wood piece. Typicallythe cutting instrument is rested on a tool rest or support block and thetool rest or support block acts as a fulcrum for the tool. Manualapplication of the tool makes it difficult to achieve consistencybetween work pieces. To allow for more consistent application whenconstructing a bowl using a lathe machine, a cutting tool may berotatably mounted via a post upon a support block slidable on the bedrails. The support block is slidably positioned and secured adjacent tothe wood piece. A cutting member having a cutting piece at its lead endextends from the post. The cutting member may then be rotated on a fixedpath into contact with the wood piece creating a fixed radius coredbowl. To bore out bowls of selectively various sizes, the cuttingmembers have consisted of a series of blades of varying curves andlengths. Using such fixed path cutting machines makes the desiredconsistency between bowls easier to achieve.

[0004] Known cutting pieces secured at the lead ends of cutting membersused to cut wood using a lathe have been known to be susceptible tocatching in the wood, causing excess vibration and excessive rotationalforces caused by the spinning wood piece. These factors in turn tend tocause excess wear on the lathe machine and damage and distortion of thecutting member, posts and various components of the lathe machine.

[0005] Cutting pieces are known to have a substantially flat or roundedupper side extending from the lead edge of a cutting member to a cuttingedge extending substantially transversely across the lead edge of thepiece. Typically, a substantially vertical and/or slightly angled leadface extends downwardly from the transverse cutting edge. The transversecutting edge is applied to the wood block attached to the lathe. Suchpieces are susceptible to catching and tend to create significantrotational force on the cutting edge as it is applied to the rotatingwood block.

[0006] Cutting pieces are also disclosed having a spear cutting pointfor application to the wood block. Although such a spear point willreduce the likelihood of catching, they are known to cause significantvibration to the machine.

[0007] Tool pitch is the rotational pulling force on the cutting edge ofthe tool caused as it is applied to the rotating block of wood. As thecutting edge extends into the wood and away from the support block ortool support, tool pitching increases.

[0008] In order to reduce the amount of pitch on the lead edge of thecutting member, various types of supports are known to be positionablebelow the lead edge of the cutting tool as it is applied to the woodblock. Such a support surface supports the cutting member as it isinitially inserted into the wood. Because the support sits directlybelow or close to the lead edge of the cutting member, lead edgepitching is reduced.

[0009] Once the lead edge of cutting tool has been insertedsubstantially into the wood block, it becomes more susceptible topitching because there is no support directly below it. As the lead edgeof the cutting member enters the wood piece when cutting a groove,supports disclosed in the prior art are not capable of following thelead edge of the cutting tool into the wood. Thus, such supports are notcapable of preventing pitching as the tool head is advanced into theblock of wood. The problem of pitching of the lead edge of the cuttingtool becomes greater when using longer cutting members curved for bowlsof larger radius, since they are separated by more distance from thetool support as they enter into the wood piece.

[0010] There is a need for an improved cutting piece or attachment forcutting wood using a lathe and there is a need for an improved systemfor forming or coring bowls using a lathe.

[0011] The present invention provides an. improved cutting piece for usewith a cutting tool that can be used to form a bowl by means of a lathe.The cutting tool attachment disclosed herein reduces the catching of thetool head when cutting into a block of wood.

[0012] According to another aspect of this invention, there is alsoprovided an improved bowl forming system which can be used with a latheand which provides support to the lead edge of a cutting tool as itadvances into the wood piece thereby reducing tool pitch and subsequentstress on the lathe and components.

[0013] In accordance with a first aspect of the invention there isprovided a cutting piece for securement to a lead end of a cutting toolcomprising a rear portion securable to the lead end of the cutting toolby a securing mechanism formed on the rear portion. A lead portion ofthe cutting piece extends forwardly from the rear portion and the leadportion having a front section is adapted to extend beyond the lead endof the cutting tool. The lead portion is narrower in a transversedirection than a forward end of the rear portion and it has twosidewalls located on opposite sides thereof. The front section has anupper side angled downwardly and forwardly and a lower side angledupwardly and forwardly. The upper and lower sides form a front end ofthe lead portion which forms a leading cutting edge. The rear portionincludes further cutting edges extending outwardly from a respective oneof the side walls of the lead portion.

[0014] According to second aspect of the invention, there is provided asystem for forming a bowl utilizing a lathe which rotates a block forthe bowl about a horizontal axis during use of the system. The systemcomprises a support block slidably engageable on the lathe bed andpositionable adjacent a face of the wood block when the block is mountedfor rotation on the lathe. A first post is mounted on the support blockand extends upwardly therefrom. An elongate cutting tool is rotatablymounted on the first post, this cutting tool including a cutting portionwhich is curved and extends to a lead end. The lead end includes acutting device for cutting and coring the block and applicable to theface of the block by rotating the cutting tool about the first post sothat the cutting device cuts a circular groove in the block about therotation axis. The cutting portion extends on a curved path toward thisaxis as the lead end advances into the block. A second post includes anupper support surface. A support member is rotatably secured on thispost and is movable thereupon from a first support position to asecondary support position. In the first support position, the secondpost is positioned adjacent the face of the block. In the secondarysupport position, the support member is arranged such that it can beadvanced into the groove directly below the cutting tool, therebyproviding support for the lead end of the cutting portion as the cuttingportion is advanced through the block.

[0015] According to a third aspect of the invention, there is provided acutting tool for use with a lathe, the tool comprising an elongate bodyportion which is curved in the lengthwise direction thereof, has twolateral sides located on opposite sides of the body portion, and has alead end with a lead portion projecting forwardly beyond the two lateralsides. The lead portion has a front section having an upper side angleddownwardly and forwardly and a lower side angled upwardly and forwardlysuch that the upper and lower sides form a leading cutting edge. Thelead portion also has two vertically extending side walls located onopposite sides thereof. The lead end of the tool is formed with outercutting edges extending transversely of the lateral sides and outwardlyfrom a respective one of the vertically extending sidewalls of the leadportion.

[0016] An advantage provided by the first and third aspect of theinvention is that the configuration of the cutting piece reduces thelikelihood of catching of the cutting piece and cutting tool as they areapplied to the block for cutting a groove.

[0017] An advantage to the second aspect of the invention is thatsupport can be provided to the lead edge of the cutting tool as itadvances into a groove created in the block, therefor reducing theamount of tool pitch and stress and reducing vibration and wear andstress on the lathe machine and components thereof.

[0018] According to a further aspect of the invention, there is provideda cutting piece for cutting a groove in a workpiece mounted in a lathe,the cutting piece comprising a rear portion securable to a lead end ofthe cutting tool and a lead portion rigidly connected to the rearportion and extending forwardly from the rear portion. The lead portionis narrower in a transverse direction than an adjacent forward end ofthe rear portion, is adapted to extend beyond the lead end of thecutting tool, and has two sidewalls located on opposite sides of thelead portion and a sloping upper side that extends downwardly andforwardly and a lower side sloping upwardly and forwardly such that theupper and lower sides form a leading cutting edge. The upper and lowersides define an angle not exceeding ninety degrees. The rear portion hasfurther cutting edges each extending outwardly from a respective one ofthe sidewalls of the lead portion.

[0019] Preferred embodiments of the invention will now be described inconjunction with the accompanying drawings.

[0020] In the drawings,

[0021]FIG. 1 is perspective view of the preferred embodiment of thecutting piece;

[0022]FIG. 2 is front elevation of the preferred embodiment of thecutting piece;

[0023]FIG. 3 is a rear side elevation of the preferred embodiment of thecutting piece;

[0024]FIG. 4 is a side elevation of the preferred embodiment of thecutting piece;

[0025]FIG. 5 is a top view of the preferred embodiment of the cuttingpiece;

[0026]FIG. 6 is a perspective view of the preferred embodiment of thecutting piece attached to a preferred cutting tool;

[0027]FIG. 7 is a perspective view of a preferred embodiment of thecutting system in a first position;

[0028]FIG. 8 is another perspective view of the preferred embodiment ofthe cutting system in this first position;

[0029]FIG. 9 is a perspective view of the preferred embodiment of thecutting system in a second position;

[0030]FIG. 10 is another perspective view of the preferred embodiment ofthe cutting system in the second position;

[0031]FIG. 11 is a further perspective view of the preferred embodimentof the cutting system in the first position which is also shown in FIGS.7 and 8;

[0032]FIG. 12 is a side view of an alternate form of curved holder forthe cutting piece of the invention; and

[0033]FIG. 13 is a top view of the curved holder of FIG. 12.

[0034] Shown in FIGS. 1 to 6 is one preferred embodiment of the cuttingpiece or attachment for cutting a groove in a workpiece such as a woodblock. The preferred embodiment of the cutting piece 10 has a rearportion 12 securable to a lead end of a cutting tool and a lead portion14 which extends forwardly from the rear portion. The lead portion has afront section 16 extending beyond the lead end 74 of a cutting tool 70.The front section has a sloping upper side 24 angled downwardly andforwardly, and a lower side 26 angled upwardly and forwardly. The upperside 24 and lower side 26 meet at a front end 28 of the lead portion toform a leading transverse cutting edge 30. Preferably the upper side 24and the lower side 26 define an angle not exceeding 90 degrees and morepreferably an angle less than 90 degrees. In one preferred embodiment,the acute angle defined between the upper side 24 and the lower side isabout 75 degrees and the preferred range for this angle is between 60and 75 degrees. The edge 30 extends substantially transversely relativeto a central longitudinal axis A extending from a rear end 31 of thecutting piece to the leading cutting edge.

[0035] Preferably the cutting piece 10 is securable to the upper surfaceof the lead end 74 of the cutting tool 70 by means of a screw 32 (seeFIG. 6) inserted through a bore 34 in the rear portion of the cuttingpiece 10 and fastened to the lead end of the cutting tool. Alternativelyit is possible to omit the bore 34 and to attach the cutting piece byother means such as brazing.

[0036] Although the preferred edge 30 extends transversely as shown, itis possible for this edge to extend at a small acute angle, for exampleup to about 10 degrees, from the perpendicular to the central,longitudinal axis A.

[0037] Preferably, the rear portion 12 has cutting edges 36 and 38 whicheach extend beyond the side walls 40, 42 of the cutting tool. Thecutting edges also extend outwardly from.a respective one of twoopposite sidewalls 41,43 of the lead portion, which is narrower in atransverse direction than a forward end of the rear portion 12. Thecutting edges 36, 38, extend beyond the side walls 40, 42 so as tocreate an effective cutting width for the groove which is greater thanthe width of the cutting tool. As shown in FIGS. 6 to 10, application ofthe cutting piece 10, secured to the lead end 74 of the cutting tool 70,to a wood block 100 rotating on a lathe 102, creates a circular groove104 in said wood 100 which has a width greater than the width of thecutting tool, thereby allowing the cutting tool to be advanced into thegroove 104. It should be noted that the spear point formed by the upperand lower sides 24, 26 acts as an effective brake to prevent thepositive cutting edges 36, 38 from being pulled into the wood block asthe cutting proceeds.

[0038] Preferably the cutting piece 10 is made of a suitable steel andincludes a plurality of longitudinal slots 48 on its bottom side, whichare configured to align with mating ridges on an upper portion of thelead end of the cutting tool 70 to help locate the cutting piece 10 onthe cutting tool and to enhance rigid securement of the cutting piece onthe cutting tool. Instead of steel, the cutting piece can be made ofother known hard cutting materials such as carbide.

[0039] Shown in FIGS. 7 to 11 is the preferred embodiment of a systemfor forming or coring a wooden bowl utilizing a lathe. The preferredembodiment includes a support block 60, slidably engageable on supportrails 62 of a lathe bed 64. The support block is releasably positionableadjacent a face of a wood block 100 which is rotatable about ahorizontal axis on the lathe 102. The support block preferably includesan elongate slot 61 on its upper surface, this slot extendingtransversely of the support rails 62 of the lathe. Preferably a firstpost 66 is mounted on the support block by bolts 68 extending throughtwo holes formed in a connecting plate at the base of the post. Thecutting tool 70 is rotatably mounted on the first post. The cutting toolincludes a cutting portion 72 which is curved and extends to the leadend 74. The lead end 74 has the cutting piece 10 extending therefrom.The cutting piece at the lead end is applicable to the face 101 of saidwood block 100 by rotating the cutting tool about the first post.Preferably, the cutting tool also includes a handle portion 76 extendinghorizontally from the rear end of cutting portion. The handle portioncan be utilized to rotate the lead end of the cutting portion intoengagement with the face of the wood block. As the wood block spins onthe lathe about the horizontal lathe axis, and the lead end withattached cutting piece is applied to the wood block face 101 so as tocut thereinto, a circular groove 104 in the wood block is created whichextends around the lathe axis. Further rotation of the cutting toolabout the first post 66 causes the lead edge of the cutting portion toextend into the wood block on a curved path. As the lead edge advancesinto the wood block, its moves closer to the axis of rotation of thewood block. As such, the diameter of the circular groove 104 diminishesas the lead edge advances into the wood block. Once the lead edgeadvances into the wood and approaches the axis of rotation of the woodblock, the lead edge causes a central portion of wood 108 to becomeseparable from the wood block. A bowl or concave cavity is formed by theremoved central wood portion 108.

[0040] The preferred system further includes a support post 80(hereinafter sometimes referred to as the “second post”) providing anupper support surface 82 and a support member 84 rotatable about thepost 80 and extending from this post in a curved path which is similarin its curvature to that of the cutting portion 72. The support post isreleasably slidable upon the upper side of the support block and isreleasably held in the desired position by means of a bolt 92 insertedthrough a slot 86 in a base plate 90 of the post. The bolt 92 extendsthrough the groove 61 in the support block and is held in the block. Thesupport post is movable from a first initial position shown in FIGS. 7,8 and 11 to a second position shown in FIGS. 9 and 10.

[0041] In the first position, the support post 80 sits adjacent to thewood block face and the lead edge of the cutting portion rests on thesupport surface. In the first support position the support surface 82sits adjacent the wood face and is positioned below the location wherethe cutting member engages the wood block thereby providing support forthe lead edge 74 of the cutting tool as it engages the wood face. In thefirst position, the supporting member 84 is rotated out of contact withthe wood block. As the lead edge 74 is advanced into the wood block, thesupport post 80 can be moved into the second position. Preferably thesupport post is moved into the second position as follows: The bolt 92is slightly loosened so as to allow the support post to move along thegroove 61 in the support block and to allow rotation and sliding of thepost about the bolt 92. In the second support position, the support postis rotated and aligned such that the support member 84 can be advancedinto the groove at a position directly below the cutting portion 72.Once the second post is located in the second position, the supportmember 84 may be advanced by advancing the support post towards the woodblock. The support post can be selectively secured and released inprogressively advanced positions by tightening and loosening the bolt92. Thus, the support member provides support for the lead edge 74 ofthe cutting tool as it is advanced into the groove. By keeping thesupport member close to the lead edge of the cutting portion, tool pitchis diminished as the cutting portion extends into the wood block.

[0042] The system described above is preferably used as follows: Theuser fixes and rotates a wood block 100 upon a lathe, rotating it abouta central horizontal axis. The support block 60 is positioned adjacentto the wood block. The cutting tool is rotated about the first post 66by the handle portion 76 and the lead edge 74 is applied to the woodface, thereby creating the circular groove 104. The support surface 82is positioned directly below the lead edge as it engages the wood facethereby providing support therefor.

[0043] As the groove 104 becomes deeper, the support post 80 is moved tothe secondary support position. The cutting portion 72 is advancedfurther into the wood block. The support member 84 is inserted into thegroove at a position below the cutting member and is advanced into thegroove providing support for the lead edge of the cutting member as itadvances into the groove, reducing tool pitch. The cutting tool 72continues to be advanced into the groove, with the support member 84providing support therefor until an internal portion of the wood blockis separated from the wood block, thereby leaving a bowl or concavecavity in the wood block.

[0044] The preferred features of the preferred cutting piece 10 will nowbe described with reference again to FIGS. 1 to 5 of the drawings. Withrespect to the rear portion of this cutting piece, the preferredembodiment has two vertically extending sidewalls 120 and 122. It willbe seen that these sidewalls taper slightly towards the centrallongitudinal axis A in a rearwards direction. At the front end of thesesidewalls are two vertically extending leading faces 124 and 126. Asillustrated in FIG. 5, where the sidewalls meet the leading faces, thecorner edges are preferably rounded or formed with a small radiusindicated at 128. These radii have not been shown in some of the figuresfor ease of illustration. The end piece has a bottom 130 which for thepurposes of this description can be considered as extending horizontally(not including the aforementioned grooves 48 formed in the bottom). Ascan be seen from FIG. 4, the preferred leading faces 124, 126 extend atan obtuse angle that is more than 90 degrees to the bottom 130. In apreferred embodiment, this obtuse angle ranges from about 95 degrees to100 degrees and is indicated by angle X. The end piece also has a top132 which is planar and which can extend at a relatively small acuteangle to the plane of the bottom 130. Thus, when the bottom 130 is in ahorizontal plane, the plane of the top 132 extends at a small acuteangle to the horizontal plane and slopes upwardly and forwardly. Inother words, the top 132 extends at a positive rake. In the illustratedembodiment, this small acute angle or positive rake is between 5 and 10degrees (most preferably 5 degrees). In this preferred embodiment, theacute angle formed between the two leading faces 124, 126 and the top ofthe end piece and indicated at Y in FIG. 4 is approximately 80 degrees.Because of the slight upward and forward slope of the top, it will beseen that the two cutting edges 36, 38 formed on opposite sides of theend piece have a positive edge geometry which is good for the freecutting of the wood. This is different than the negative geometry formedby the spear point created by the aforementioned upper side 24 and thelower side 26. The advantage of the negative geometry of the spear pointformed by the lead portion 14 is that it is non-catching when applied tothe rotating wood block.

[0045] In an alternate form of the cutting piece 10, the top 132 isparallel to the plane of the bottom 130 and this cutting piece is thenmounted on a cutting tool holder such as that shown in FIGS. 12 and 13so that its top 132 will extend in use at a small angle to thehorizontal plane, i.e. five degrees.

[0046] It will be seen from the above description of FIGS. 7 to 11 thatthe cutting tool 70 has a vertical pivot axis formed by its supportpost. It can be moved in two horizontal directions during use of thecutting tool. Thus the post 66 can be moved horizontally along thesupport rails 62 by adjusting the position of the support block 60 andit can also be moved transversely of the support rails 62 by adjustingthe position of the post along the slot 61 (using the aforementionedadjustment bolt 68). By being able to move the support post 66 in thesetwo different horizontal directions, the centre point of the radius ofthe cutting portion 72 can be moved. This advantage together with theprovision of cutting portions 72 of cutting tools having different radiiprovides the possibility of producing a wide variety of bowl sizes usingthe system of the invention.

[0047] Another preferred feature of the present system is the manner inwhich the cutting tool 70 is mounted on the post 66. As shown in FIGS. 7and 9, for example, there is a short upward vertical extension of thepost at 140. Mounted on the top of this extension is a bent bar 142which has a horizontally extending section 144 and then a Z-shapedsection 146 to which the aforementioned handle 76 is connected. It willbe particularly noted that the top of the horizontally extending section144 is positioned below the axis for rotation of the lathe. It will beunderstood that this axis for rotation is located approximately in thecenter of the wood block from which the bowl is being formed. Theadvantage of supporting a cutting tool in this manner is that thisarrangement enables the standard tail stock (not shown) of the lathe tobe used, if required to support the wood block as it is being rotated.In other words the tail stock can be engaged with the centre of the faceof the wood block 100 in which the groove 104 is being formed. Thus atvarious times during the use of the system of the invention, the tailstock of the lathe can be used to prevent excess vibration which couldotherwise be a problem, particularly on a weaker lathe machine.

[0048]FIGS. 12 and 13 illustrate an alternate configuration for thecurved tool holder that holds and support the cutting piece 10. Thisalternate curved tool holder 150 can be used in place of the cuttingportion 72 shown in FIGS. 6 to 11 of the drawings. As with the versionshown in FIGS. 6 to 11 this tool holder extends through a circular arcfrom a rear end 152 to its lead end 154. In one particular embodimentthis arc has a radius of 6.81 inches but the radius can clearly varydepending upon the particular coring requirements. The holder can bemade from a strip of steel which has a width in one particularembodiment of 1.50 inches. The holder 150 has a relatively narrow orshort front end section 156 on which the cutting piece 10 can bemounted. There is a sloping section at 158 where the top edge 160 of theholder slopes down to the front end section 156. In the illustratedembodiment, the angle Z of the slope is about 30 degrees. Also in apreferred embodiment the thickness of the steel strip forming the holderis 0.25 inch. A threaded bore 162 is formed in the front end section 156and, as indicated, this bore is sized to receive a screw used to holdthe cutting piece.

[0049] It will be particularly noted that the top edge at 164 of thefront end section extends at a small angle to the horizontal and at thesame small angle to the main portion of the top edge on the rear sectionof the holder. In one preferred embodiment, this small angle is 5degrees with the top edge section 164 sloping downwardly and rearwardly.The advantage of this configuration is that the cutting piece 10 canthen be made with parallel top and bottom surfaces. By mounting thecutting piece on a slightly sloping surface, the top 132 of the cuttingpiece will then be sloped at a small acute angle downwardly andrearwardly in the preferred manner.

[0050] It has been found that with the use of the cutting piece andcutting tool of the invention and with the use of the above describedsystem for forming a bowl, a wood bowl can be produced which has a goodfinish with the wood fibres cleanly severed. In addition with the use ofthe cutting devices in the aforementioned system, a user generally hasno difficulty coring the wood block to where the wood core will breakout with only a slight tap or will simply fall out, a result which isgenerally not obtained with other known methods.

[0051] Since various modifications can be made in the invention ashereinabove described, and many different embodiments of same can bemade within the spirit and scope of the invention, it is intended thatall matter contained in the above specification shall be interpreted asillustrative only and not in a limiting sense. All variations andmodifications of this invention as fall within the scope of theaccompanying claims are intended to be part of this invention.

1. A cutting piece for securement to a lead end of a cutting tool comprising: a rear portion securable to said lead end of said cutting tool by securing means formed on said rear portion, and a lead portion extending forwardly from said rear portion, said lead portion being narrower in a transverse direction than a forward end of said rear portion, having a front section adapted to extend beyond the lead end of said cutting tool, and having two sidewalls located on opposite sides of said lead portion, said front section having an upper side angled downwardly and forwardly and a lower side angled upwardly and forwardly such that said upper and lower sides form a front end of said lead portion and said front end forms a leading cutting edge; wherein said rear portion includes further cutting edges each extending outwardly from a respective one of said sidewalls of said lead portion.
 2. A cutting piece according to claim 1 wherein said cutting piece is made of steel and wherein said upper side and said lower side define an angle not exceeding 90 degrees.
 3. A cutting piece according to claim 1 or 2 wherein said securing means is a bore formed in the rear portion and adapted to receive a screw for attachment of said cutting piece to said lead end of said cutting tool.
 4. A cutting piece according to any one of claims 1 to 3 wherein said rear portion includes a bottom side having a plurality of horizontal grooves which are releasably engageable with mating ridges on an upper side of said lead end of said cutting tool.
 5. A cutting piece according to any one of claims 1 to 4 wherein said rear portion has an upper side and leading, vertically extending faces from which said lead portion extends and said further cutting edges are formed where said vertically extending faces meet said upper side.
 6. A cutting tool for use with a lathe, said cutting tool having a lead end and first and second sidewalls and a cutting piece formed on said lead end and comprising a rear portion and a lead portion extending forwardly from said rear portion, said lead portion being narrower in a transverse direction than a forward end of said rear portion and having two sidewalls located on opposite sides of said lead portion, said lead portion having an upper side angled downwardly and forwardly and a lower side angled upwardly and forwardly such that said upper and lower sides form a front end of said lead portion and said front end forms a leading cutting edge, wherein said rear portion includes further cutting edges each extending outwardly from a respective one of said sidewalls of said lead portion.
 7. Use of the cutting piece according to any one of claims 1 to 5 secured to said lead end, to cut a block rotating on a lathe, whereby said cutting piece creates a groove in said block of greater width that the width of said cutting tool thereby allowing said cutting tool to be advanced into said groove.
 8. A cutting tool for use with a lathe, said tool including an elongate body portion which is curved in the lengthwise direction thereof, has two lateral sides located on opposite sides of said body portion, and has a lead end with a lead portion projecting forwardly beyond said two lateral sides, said lead portion including a front section having an upper side angled downwardly and forwardly and a lower side engled upwardly and forwardly such that said upper and lower sides form a leading cutting edge, said lead portion also having two vertically extending sidewalls located on opposite sides thereof, wherein said lead end is formed with outer cutting edges extending transversely of said lateral sides and outwardly from a respective one of said vertically extending sidewalls of said lead portion.
 9. A cutting tool according to claim 8 wherein a separable cutting piece forms said lead portion and said outer cutting edges and said elongate body portion includes a curved, elongate holder for said cutting piece, said cutting piece being attached to said elongate holder by a threaded fastener.
 10. A cutting tool according to claim 9 wherein said cutting piece includes a rear portion having a bore extending therethrough and said threaded fastener extends through said bore in order to attach said cutting piece to said curved, elongate holder.
 11. A cutting tool according to any one of claims 8 to 10 wherein said upper side and said lower side define an acute angle that is less than 90 degrees.
 12. A system for forming a bowl utilizing a lathe which rotates a block for said bowl about a rotation axis during use of the system, said system comprising: a support block slidably engageable on a bed of said lathe and positionable adjacent a face of said block when said block is mounted for rotation in said lathe; a first post mounted on said support block and extending upwardly therefrom; an elongate cutting tool rotatably mounted on said first post, said cutting tool including a cutting portion, said cutting portion being curved and extending to a lead end, said lead end including cutting means for cutting and coring said block and during use of said cutting tool being applicable to said face of said block by rotating said cutting tool about said first post so that said cutting means cuts a circular groove in said block about said rotation axis, said cutting portion extending on a curved path toward said axis as said lead end advances into said block; a second post releasably mountable on said lathe and movable thereon from a first support position where said second post is adjacent said face of the block to a secondary support position; and a curved support member rotatably secured on said second post, wherein, in said secondary support position of said second post, said curved support member is arranged such that it can be advanced into said groove directly below said cutting tool, thereby providing support for the lead end of said cutting portion as said cutting portion is advanced through said block.
 13. A system according to claim 12 wherein said support block includes a slot extending across an upper surface of the block and both said first and second posts are secured to said support block by means of bolts secured in said groove.
 14. A system according to claim 13 wherein said second post has a base portion with a slot formed therein and said second post is secured to said support block by one of said bolts extending through said slot of the base portion and into said slot in said support block.
 15. A system according to claim 14 wherein said second post is movable from said first support position to said secondary support position by rotating said second post about said one bolt and sliding said one bolt within said slot of the support block and said support member is advanced into said groove by moving said base portion horizontally relative to said one bolt.
 16. A system according to any one of claims 12 to 15 wherein said cutting means is a separable cutting piece rigidly secured to the lead end of said cutting portion, said cutting piece having a leading cutting edge.
 17. A system according to claim 16 wherein said cutting piece is the cutting piece of claim 1, 2 or
 3. 18. A method of using a system according to any one of claims 12 to 17 comprising: fixing and rotating said block for the bowl upon a lathe for rotation about said rotation axis; positioning said support block adjacent said block; rotating said cutting tool about said first post and applying said lead end to the face of the block for the bowl; positioning said support member below said lead end as said lead end is applied to said face and thereby providing support therefor; advancing said cutting portion with said cutting means into said block and thereby forming said circular groove in said block for the bowl; and advancing said support member into said circular groove at a position below said cutting portion as said cutting portion advances into said block and thereby providing support for said cutting portion and said cutting means as they advance into said circular groove.
 19. A method according to claim 18 including an additional step of moving said second post from said first support position to said secondary support position after said cutting portion and said cutting means have been advanced into said circular groove a distance such that further advancement of said cutting portion and said cutting means requires such second post to be moved to said secondary support position so that said cutting portion and said cutting means are adequately supported.
 20. A method according to claim 18 or 19 wherein both said cutting portion and said support member are continuously advanced into said circular groove along a curved path toward said rotation axis until an internal portion of said block for the bowl can be readily separated from a surrounding portion of said block.
 21. A cutting piece for cutting a groove in a workpiece mounted in a lathe, said cutting piece comprising a rear portion securable to a lead end of the cutting tool and a lead portion rigidly connected to said rear portion and extending forwardly from said rear portion, said lead portion being narrower in a transverse direction than an adjacent forward end of said rear portion, being adapted to extend beyond said lead end of the cutting tool, and having two sidewalls located on opposite sides of said lead portion and a sloping upper side that extends downwardly and forwardly and a lower side sloping upwardly and forwardly such that said upper and lower sides form a leading cutting edge, wherein said upper and lower sides define an angle not exceeding ninety degrees and said rear portion has further cutting edges each extending outwardly from a respective one of said sidewalls of said lead portion.
 22. A cutting piece according to claim 21 wherein said leading cutting edge extends substantially transversely to a central longitudinal axis of the cutting piece.
 23. A cutting piece according to claim 21 or 22 wherein said rear portion has a top surface and leading faces from which said lead portion extends, said further cutting edges being formed where said leading faces meet said top surface.
 24. A cutting piece according to claim 23 wherein said top surface of the rear portion slopes upwardly in a forwards direction towards said lead portion when said cutting piece is secured to said lead end of said cutting tool.
 25. A cutting piece according to any one of claims 21 to 24 wherein said rear portion includes a bottom side having a plurality of horizontal grooves which are releasably engageable with mating ridges on an upper side of said lead end of said cutting tool.
 26. A cutting piece according to any one of claims 21 to 24 wherein said rear portion has a vertically extending bore extending therethrough, said bore being provided for a screw that can be used to secure said cutting piece to said cutting tool.
 27. A cutting piece according to any one of claims 21 to 26 wherein said upper and lower sides define an acute angle of approximately 75 degrees. 